KAGAKU KOGAKU RONBUNSHU
Online ISSN : 1349-9203
Print ISSN : 0386-216X
ISSN-L : 0386-216X
Volume 26 , Issue 5
Showing 1-23 articles out of 23 articles from the selected issue
  • SHIZUO MIDORI, SHUANG NING ZHENG, IKUHO YAMADA
    2000 Volume 26 Issue 5 Pages 627-632
    Published: September 10, 2000
    Released: March 15, 2010
    JOURNALS FREE ACCESS
    The divided-wall column (hereinafter called DWC) has received widespread attention in terms of its compact structure and high thermal efficiency, which offers savings in capital and energy costs, since it was originally reported by Wright and Elizabeth in 1949. Some DWCs, have already been commercialized successfully including that of the authors in 1996. However, with the existing DWC construction, they cannot be applied to the separation of azeotropic systems or close boiling component systems, and the application has been limited to ordinary ternary systems, i. e. the separation of light, middle, and heavy fractions.
    In this paper, a new extractive distillation column that the concept of DWC can be applied to is shown, and a comparison with the conventional two-column sequence has been presented in terms of process compactness and heat intergration. The devised column here is called DWC-E, and it has the following features:
    1) DWC-E is divided from the column top to the midportion between the feed plate and the bottom by a vertical wall (splitting plate), and 2) DEC-E is compact-type process with only two top condensers and one reboiler. Moreover, a simulation of acetone-methanol-water extractive distillation is carried out to examine the validity of DWC-E. The result shows that DWC-E can save a maximum of 36% energy consumption compared to the conventional two-column sequence.
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  • TOMIO MIMURA, KOUJI MATSUMOTO, MASAKI IIJIMA, SHIGEAKI MITSUOKA
    2000 Volume 26 Issue 5 Pages 633-636
    Published: September 10, 2000
    Released: March 15, 2010
    JOURNALS FREE ACCESS
    Carbon dioxide removal was carried out on LNG combined cycle Power station flue gas up to about 3% CO2 concentration, using a pilot-scale absorber of about 23 m height at an exhaust gas flow rate of 770m3/h. Test results show a chemical absorption process using KS-1 solution, which is a hindered type alkanolamine, exhibits good applicability to the present condition. The degree of CO2 removal is higher than 90% in the range of CO2 concentration of 3.4% to 10.3% by the selection of the proper steam consumption. The thermal energy increases as the CO2 concentration decreases. In the case of KS-1 solution, the thermal energy is as low as 3.5×103kJ/kg CO2, even at a CO2 concentration of 3.4%.
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  • SHIGEO GOTO, TOMOHIKO TAGAWA, HAJIME ITOH
    2000 Volume 26 Issue 5 Pages 637-642
    Published: September 10, 2000
    Released: March 15, 2010
    JOURNALS FREE ACCESS
    The membrane reactor in this work is a double tubular reactor equipped with a palladium-ceramic composite tube as inner tube and packed with catalysts in the annular part between the inner and outer tubes. Further, two kinds of baffle rings are in turn inserted into the catalytic bed to decrease radial gradients of concentration and temperature profiles by regulating gas flow patterns.
    This proposed reactor is simulated by using dehydrogenation of cyclohexane as a model reaction. The efficiency of baffle rings was confirmed by calculating the conversions and mole fractions of hydrogen iunder various conditions of total pressure, temperature, and feed mole fraction, as well as the standard conditions.
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  • TAKENORI TANAKA, KEIJI TAKEUCHI, MASAHITO TAYA
    2000 Volume 26 Issue 5 Pages 643-648
    Published: September 10, 2000
    Released: March 15, 2010
    JOURNALS FREE ACCESS
    A malfunction diagnosis system based on fuzzy inference was developed for industrial scale fermentation with an alkaliphilic cellulase-producing bacterium. The index J indicating the degree of malfunction in the fermentation process is calculated from the deviations of actual values from the standard values with respect to three kinds of process data obtained from on-line sensors. The diagnosis system proposed in this study is as follows.
    The fermentation process is automatically categorized into one of three states (normal, intermediate and abnormal) according to computation of the J value. Only when the fermentation process is categorized to an “intermediate” state, an operator should supervise the process by means of direct observation of process data.
    The diagnosis system was applied to 100 runs of batch fermentations conducted on an industrial scale. In all cases, it was confirmed that this system worked to offer the correct diagnosis results. The introduction of the system resulted in the reduction of over 99% in the operators' diagnosing labor because their supervising tasks could be limited to the intermediate cases.
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  • SHUICHI SEGAWA, YUTAKA MITANI, KAZUNARI OHGAKI
    2000 Volume 26 Issue 5 Pages 649-653
    Published: September 10, 2000
    Released: March 15, 2010
    JOURNALS FREE ACCESS
    In a solution of macromolecules such as proteins that have surface activity, the macromolecules stabilize the foam by adsorbing at the bubble surface. These surface-active macromolecules at the gas/liquid interface lower surface energy. The macromolecules adhere to the gas/liquid interface, and then change their shapes. Hydrophobic groups in the molecule turn to the gas phase and hydrophilic groups turn to the liquid phase. The macromolecules separated from beer were dissolved in an acetic acid buffer solution, and then the surface behavior was speculated by the surface tension change. Their surface tension did not reach a constant value for several seconds, not like the low molecular solutions such as ethanol. The decrease in this surface tension could be kinetically analyzed. The surface tension decreased by the adsorption of macromolecules on the liquid surface, and by the shape changes in the molecule (the extension of molecule at thesurface). In the β-casein solution, the surface tension decreased in 2 steps that were more clear than in the beer macromolecule solution. This surface tension decrease is also supposed to show the adsorption of protein molecules and the shape change at the liquid surface.
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  • EIJI SHINODA, ATSUSHI SUGITATE, KUNIHIRO FUKUI, HIDETO YOSHIDA
    2000 Volume 26 Issue 5 Pages 654-660
    Published: September 10, 2000
    Released: March 15, 2010
    JOURNALS FREE ACCESS
    Numerical simulation and experimental studies have been conducted on dynamic characteristics of powder flow rate and particle size distribution for the initial stage of a closed-circuit pulverization system.
    The performances of pulverizer and classifier are modeled by use of experimental data. The returning powder flow rate is taken into consideration and material balance equations of each size range are numerically solved by an iterative method.
    Numerical simulations were conducted for three types of control method. Feed rate control, rotor speed control of the palverizer and bypass control of the classifier for a given time of initial stage were simulated.
    The shortest stabilization time was realized in proportional control of feed rate, and stabilization time was one third compared with normal operation. By use of bypass control of the classifier, the total product power until steady state is minimum.
    Experimental data by feed rate control operation agrees with the simulational results, and reliability of the present simulational method is confirmed.
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  • TATSUSHI NISHI, AKIHIRO SAKATA, SHINJI HASEBE, IORI HASHIMOTO
    2000 Volume 26 Issue 5 Pages 661-668
    Published: September 10, 2000
    Released: March 15, 2010
    JOURNALS FREE ACCESS
    An autonomous decentralized scheduling system, which aims at minimizing the sum of changeover cost, storage cost, and due-date penalty, is proposed for flowshop problems. In the proposed system, the scheduling system belonging to each production stage gradually generates a plausible schedule through repeated generation of schedules for the stage and repeated exchange of data among the production stages. When intermediate storage cost is included in the objective function, calculation of the optimal starting times of jobs is fairly difficult, even if the production sequence of jobs at each stage is fixed. In this study, an algorithm for effective calculation of the starting times of jobs, which can minimize the storage cost, has been developed. By embedding this algorithm in the scheduling algorithm, an autonomous decentralized scheduling system, which realizes Just-in-Time production at all production stages, is developed. It is also shown that the proposed system is applicable to the case in which the space available for intermediate storage is limited. The results of example problems show that the schedules obtained by the proposed system are significantly better than those obtained by conventional methods.
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  • MITSUO KAMIWANO, MEGURU KAMINOYAMA, KAZUHIKO NISHI, AYAKO MIZUSHIMA
    2000 Volume 26 Issue 5 Pages 669-674
    Published: September 10, 2000
    Released: March 15, 2010
    JOURNALS FREE ACCESS
    When slurry liquids with suspension of high concentration of fine solid particles are stirred with a small-diameter impeller like a paddle in a vessel, the flow region around the impeller and the outer stagnant region, where the flow velocity is negligibly small, are formed in the vessel, due to the yield stress of the liquids.
    In this study, we present a method of thermally determining the boundary between both regions. The measuring principle of the method is as follows; Under the condition of heating the liquids in a stepwise way with the heat source set just below the impeller, we measure dynamic changes of temperatures at two points with electrical thermocouples; one is a standard point set in the vicinity of the impeller tip in the flow region, and the other is an arbitrary measuring point in the vessel. The temperature difference in the two points decreases rapidly at the flow region around the impeller where the convection is dominant in heat transfer, while the difference increases dynamically in the outer stagnant region where the conduction is superior. We can, therefore, judge from the dynamic change whether arbitrary measuring point in the vessel is in the flow or stagnant region, even for opaque slurry liquids.
    It was found as a result that the region in the vessel can be differentiated, by this thermal method, into three regions, a complete flow region, a stagnant region, and an intermediate boundary region.
    We ascertained that the flow regions involving the boundary region are in good agreement with the results by coloring visualization experiments, as well as numerical calculation results using a simplified model and, therby, verified the reliability of the method proposed in this study.
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  • SHIGETOSHI ICHIMURA, TAKEO YAMAGUCHI, SHIN-ICHI NAKAO
    2000 Volume 26 Issue 5 Pages 675-682
    Published: September 10, 2000
    Released: March 15, 2010
    JOURNALS FREE ACCESS
    The retention properies of two porous glass membranes (SPG membranes) of different pore size ware measured with linear macromolecular solutes. The dependence of real rejection on volume flux indicates the membrane is composed of two layers, thus the values of reflection coefficients for surface and inner layers (σA and σB) and solute permeability for surface layer (PA) were determined with Jagur -Grodzinski and Kedem equation by means of a curve-fitting method. Pore radii for surface and inner layers (rpA and rpB) were evaluated from σA and σB, respectively, by comparing with the theoretical curves predicted by the original pore (OP) model and the steric-hindrance pore (SHP) model. The hydraulic permeability and the results of mercury porosimetry measurement show the OP can could be applied to the structural characterization, while the SHP model underestimated the pore radii. As a result, a value of 1.4 is obtained as the ratio of rpA to rpB for both membranes, and the thickness of the surface layer is found to be less than 1μm from PA by the OP model analysis.
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  • KEI IMAFUKU, YUH YAMASHITA, HIROKAZU NISHITANI
    2000 Volume 26 Issue 5 Pages 683-686
    Published: September 10, 2000
    Released: March 15, 2010
    JOURNALS FREE ACCESS
    In this paper, we solve an optimal control problem to get a high yield of a product by using the characteristics of oscillatory autocatalytic reaction in continuous stirred-tank reactor (CSTR). First, we formulate a problem of maximizing the yield on a finite horizon at each present time. Next, we propose a new method to get a set of optimal input moves in real-time at each sampling step by a searching method which utilizes random inputs. The effectiveness of the proposed method is shown through some simulations.
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  • YOSHITOSHI NAKAMURA, FUMIHISA KOBAYASHI, TATSURO SAWADA, KAZUO YAMAGUC ...
    2000 Volume 26 Issue 5 Pages 687-692
    Published: September 10, 2000
    Released: March 15, 2010
    JOURNALS FREE ACCESS
    In order to produce a glucoamylase rapidly and efficiently, the breeding and incubation of recombinant Escherichia coli having a genetically engineered overexpression system were investigated experimentally. The recombinat E. coli BL 21 (DE 3) [pET-12-STA 1] having an overexpression system with a recombinant plasmid (pET-12-STA 1) was constructed by inserting a STA1 gene (a glucoamylase gene) into an overexpression vecter (pET-12). Though the conventional recombinant E. coli JM 109 [pET-12-STA 1] synthesized only a little glucoamylase, the recombinant E. coli BL 21 (DE 3) [pET-12 -STA 1] produced about 3U/ml of glucoamylase. The optimal conditions for producing the glucoamylase were determined by changing the carbon sources, pH, and the metal ions in the culture medium. In a M 9 minimal medium using glucose as a carbon source at pH 7, the recombinant E. coli produced a large amount of glucoamylase. Furthermore, the addition of sodium ions to the culture medium enhanced not only the production but also the secretion of glucoamylase. The maximum extracellular glucoamylase activity obtained in this work was 6.6U/ml and this value was much higher than that secreted in the conventional LB medium, i. e. 0.002U/ml.
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  • JUN MORIMOTO, YOSHIYUKI YAMASHITA, MUTSUMI SUZUKI
    2000 Volume 26 Issue 5 Pages 693-697
    Published: September 10, 2000
    Released: March 15, 2010
    JOURNALS FREE ACCESS
    Although the optimal regulator is widely known as a typical optimal-feedback controller, the optimal problem for multi-variable non-linearsystems is hard to solve in real-time. In this paper, a new method for solving the optimal regulator is proposed. Optimal values of manipulation variable are calculated by evaluating an objective function on state-variable space which is iteratively solved by a dynamic programming. As a result of simulation for level-control of a tank and temperature-control of a CSTR, the proposed method provides real-time calculation of the optimal problem, and a good controller can be realized. Consecutive calculation of optimal regulator realizes tracking controller of a batch process with quasi-steady state condition. Simulation of reflux-ratio control of a batch distillation shows good control performance.
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  • TSUYOSHI KONDO, YOSHIKAZU MIYAKE
    2000 Volume 26 Issue 5 Pages 698-704
    Published: September 10, 2000
    Released: March 15, 2010
    JOURNALS FREE ACCESS
    When titanium tetra-isopropoxide (TTIP) is dissolved in a hydrochloric solution, a transparent titania sol solution forms. The precipitate of titania is obtained by aging the mixing solution of the titania sol and a surfactant for 48 hours at 60°C.
    In the presence of SDS, the formation rate of the precipitation increases with increasing SDS to TTIP molar ratio, and the crystal structure of titania changes from rutile to anatase. The specific area and pore volume of the calcined titania are larger than that of the titania prepared in no surfactant. The results show that SDS functions as a template to prepare the mesoporous titania. Under TTIP: SDS=1: 1, the powder XRD pattern of the as-synthesized precipitate has a peak at 2θ=3.2°. The result shows that the precipitate has a regular microstructure of nanometer size, but the microstructure is destroyed by the calcination. In both cationic and nonionic surfactants systems, the structure of titania is rutile, because the formation rate of precipitate is very slow. The specific surface area and pore volume are almost the same as that prepared with out surfactant. These results show that both surfactants don't function as templates.
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  • HIDEO IWAHASHI, MASAHIRO KISHI, OSAMU MIYATAKE
    2000 Volume 26 Issue 5 Pages 705-710
    Published: September 10, 2000
    Released: March 15, 2010
    JOURNALS FREE ACCESS
    With regard to mass transfer in a seawater flow channel of a hollow fiber module used for seawater desalination, the seawater flow channel in an infinitesimal space is taken as a model of a flow channel in a circular tube and between similarly parallel flat plates.
    An analytical solution of velocity distribution and a numerical solution of concentration distribution are obtained from fundamental equations by use of a separation procedure of variables. As a result, the ratio of concentration polarization on a membrane surface is determined by salt rejection and a dimensionless volumetric flux of water through the membrane, that is, a product of the volumetric flux of water through the membrane and the half width of the flow channel are divided by a diffusion coefficient.
    It has become clear that under practical operating conditions, the ratio of concentration polarization can be ignored. There is almost no difference between a seawater flow channel model with parallel flat plates and another model in the form of a circular tube. On the other hand, the calculated thickness of a concentration boundary layer is much larger than the width of the seawater flow channel in a conventional equation of mass transfer, which is expressed as a function of Reynolds number. It seems that this may be mistaken for a non-uniform flow not related to diffusion resistance.
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  • TATSUO NISHIMURA, HIDEO KAWAHARA, KENICHI MORIO
    2000 Volume 26 Issue 5 Pages 711-719
    Published: September 10, 2000
    Released: March 15, 2010
    JOURNALS FREE ACCESS
    Vortical and thermal structures of a non-premixed propane flame in a bluff-body burner are studied experimentally in the transition from laminar to turbulent flow. In particular, we focus attention on the effect of annular air flow on the flame. The increase in the annular air flow promotes development of a shear vortex street in the central fuel jet and also leads to change in the direction of rotation of the shear vortex. The vortex dynamics correspond well to the fluctuation in temperature and there is a peak in rms temperature inside and outside the flame, respectively. It is revealed that the annular air flow has a stronger impact on the flame, rather than the central fuel jet, in this experimental range.
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  • YUICHI OHIRA, SATOSHI YAMADA, YOSHIKAZU KUGA, EIJI OBATA, KOJI ANDO
    2000 Volume 26 Issue 5 Pages 720-722
    Published: September 10, 2000
    Released: March 15, 2010
    JOURNALS FREE ACCESS
    The effect of the initial nitrite concentration on the growth of S. platensis was experimentally investigated using the medium added to the sodium nitrite of 0.0-1.6kg·m-3. When the initial nitrite concentration is smaller than 0.8kg·m-3, the growth rate is greater than that without nitrite. The specific growth rate had the maximum value and is approximately 1.3 times that of a standard medium when the range of the initial nitrite concentration is 0.3-0.4kg·m-3. When the initial nitrite concentration is greater than 0.8kg·m-3, the growth rate was smaller than that of a standard medium due to nitrite inhibition.
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  • YOSHITOMO HANAKUMA, JUNZOU YAMAMOTO
    2000 Volume 26 Issue 5 Pages 723-726
    Published: September 10, 2000
    Released: March 15, 2010
    JOURNALS FREE ACCESS
    A method of fuzzy clustering has a weak point of falling in local optimum track. The method of clustering by genetic algorithm has been proposed. A method has the advantage of data clustering in industrial use. It was applied to data clustering of products property which has 40 relations between the moony viscosity and additive diene material in EPDM plant to confirm the performance. The actual result indicates that the method of clustering by genetic algorithm is effective in practical data clustering.
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  • MUNEHIRO ISHIOKA, MASAHIDE MORIKAWA, HIDEKAZU MARUKAWA
    2000 Volume 26 Issue 5 Pages 727-730
    Published: September 10, 2000
    Released: March 15, 2010
    JOURNALS FREE ACCESS
    In order to improve the prediction precision of the coating weight for the squeeze rolls with diminutive V-shaped grooves, the influence of line speed on coating weight and a model for a liquid amount transferred to strip are discussed.
    The influence of line speed is attributable to the viscous force occurring in the groove, and the force is estimated to be equal to that for the equivalent positive-gap in the forward roll coating with rigid rolls. The film thickness is also estimated from the published result for the forward roll coating. Our model is confirmed to be reasonable, compared with the experimental results.
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  • SHUILIANG YAO, FENG OUYANG, AKIRA NAKAYAMA, EIJI SUZUKI, MAMORU OKUMOT ...
    2000 Volume 26 Issue 5 Pages 731-733
    Published: September 10, 2000
    Released: March 15, 2010
    JOURNALS FREE ACCESS
    Coupling and reforming of methane with carbon dioxide were studied at room temperature and 773 K in a pulsed plasma. Methane and carbon dioxide could be converted mainly to ethylene, carbon monoxide, and hydrogen at room temperature. At 773K, the main product was ethane at a low pulse frequency and ethylene at a high pulse frequency. The energy efficiency can be significantly improved by using a high pulse frequency and high temperature.
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  • SHUJI SAKOHARA, TAKASHI KIMURA, KAZUO NISHIKAWA
    2000 Volume 26 Issue 5 Pages 734-737
    Published: September 10, 2000
    Released: March 15, 2010
    JOURNALS FREE ACCESS
    Flocculation of suspended particles by a thermosensitive polymer which shows a reversible hydrophilic/hydrophobic transition by heating or cooling its aqueous solution is examined. Poly (Nisopropylacrylamide) (poly NIPAM), whose transition temperature is about 32°C, is used as a thermosensitive polymer. Flocculation experiments were performed by a jar test with kaolin suspension. In the case of operating temperature lower than the transition temperature of poly NIPAM, there is an optimum polymer dosage, and by dosing excessively, kaolin particles are stabilized in the same manner as conventional polymeric flocculants. By heating the suspension above the transition temperature under the excess polymer dosage, however, the floc formation is observed. Furthermore, by cooling the suspension including flocs below the transition temperature again, the flocs were disorganized to the stabilized particles. From these phenomena, it can be concluded that the floc formation caused by heating above the transition temperature is due to the hydrophobic interaction of poly NIPAM molecules absorbed on the particles.
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  • HIDEHIRO KAMIYA, SACHIKO KAGAWA, MASAO AZAGAMI, MASAYUKI HORIO
    2000 Volume 26 Issue 5 Pages 738-740
    Published: September 10, 2000
    Released: March 15, 2010
    JOURNALS FREE ACCESS
    In this paper, the catalytic effect of both Cl contained within RDF and addition of Ca on NOx generation during RDF combustion in fluidized beds are discussed. NOx generation was examined using a simulated flue gas permeation test with NH3 through a limestone particle packed bed. It was confirmed that mixing with gaseous HCl increased NOx conversion. After the permeation test with gaseous HCl, fine particles below 1μm in diameter were formed on the surface of the limestone particles. It appears that the increased surface area of the limestone particles promoted the catalytic effect on NOx generation.
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  • YUKIO ENDA, KATSUYASU SUGAWARA, TAKUO SUGAWARA
    2000 Volume 26 Issue 5 Pages 741-744
    Published: September 10, 2000
    Released: March 15, 2010
    JOURNALS FREE ACCESS
    A new control method was developed for toxic metal ion elution from fly ash in an acid solution. Coated fly ash pellets were prepared by covering with bottom ash produced from the same coal-fired boiler and subsequent sintering at 1, 300°C.
    The elution test was carried out in the acid solution of pH 3, 4 and 5.5 for the fly ash pellets with and without the bottom ash coating. The coating of fly ash pellet suppresses the elution of lead ion, independent of acidity of solution, while the fly ash pellet without coating shows an increase of lead elution with lowering of pH.
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  • MASAFUMI KURIYAMA, HIDEKI TOKANAI, EIJI HARADA
    2000 Volume 26 Issue 5 Pages 745-748
    Published: September 10, 2000
    Released: March 15, 2010
    JOURNALS FREE ACCESS
    A correlation equation for the maximum stable drop size is derived theoretically, by taking into account the flow behaviors of pseudoplastic dispersed-phase liquids. The flow behaviors are well formulated with the power law model whose rheological constants are consistency and flow index. The derived correlation equation is an extended formula of the previously proposed one for Newtonian dispersed-phase liquids. The validity of the new correlation equation is confirmed through agitation dispersion experiments over a wide range of dispersed-phase consistencies or flow indices.
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